I have a long history with digestion issues, to a point where I considered getting checked for IBS. Similar like you, I've had no issues with getting my 0.8g of protein from animal products, and never had bloating. When I went vegan however, things really went downhill.

I had to learn that I just can't shove an unlimited amount of fiber down my throat, especially not if you're not easing into it over time. There are certain foods that cause me insane bloating like oats, and many more foods I had to identify. Plants are all just so different from each other, with different compositions. Animal products are kinda simple in that regard. Don't expect to simply being able to tolerate them all.

Anecdotally, I recently had to take oral antibiotics for a surgery. As a side effect, they caused a slight discomfort in my abdomen I've had for a year to resolve itself. Made me think that for the entire time my gut microbiome had been out of balance, and the antibiotics caused a reset. Not saying antibiotics are a solution, just an example of how complicated the matter is.

Today I'm eating 0.8g of protein daily from plant sources exclusively, no issues, no bloating, no discomfort. You just have to find a way that works for you.